Switch



Nov. 24, 1953 J, w, WOOLF 2,660,627

SWITCH Filed Sept. 18. 1948 2 Sheets-Sheet l y @Cr/Z f/Zarney.

J. W. WOOLF SWITCH 2 Sheets-Sheet 2 Filed Sept. 18. 1948 4 6 aw W 7 ,f M f 67?# Ao 4 ffl 4 1|- 2 0 e 6 www 2 7 .o 6 m; 4 M

wf y. @d m n@ y E e. om w+# Z l@ F a Y m J y miv@ z f Patented Nov. 24, 1953 aesozi SWITCH James W. Woolf, Franklin, Pa.,

Manufacturing Company,f Pittsburgh`, Pa., a corporation of Pennsylvania Application September 18, 16948,' Serial o. (c1. 200:5)

9 Claims.

This invention relates to switches, especially to a pedally operatedswitch suchas may be used in; certain special automotive applications, as, for example, mine shuttle cars.

In any mechanized industry it is lhighlydesirableto cut the idle time of equipment down to a minimum. Time during which equipment has to be outof use becauseof maintenance involves a loss of the use of the capital invested in the equipment for the time that the equipment is idle. It is accordingly advantageous in any mechanized industry to have equipment which is designed for easy maintenance with as little shutdown time as possible,l in order that the investment represented in the equipment may not be ldleany longer than necessary. To this end, the equipment should be' designed as simply as possiblefor quick and easy maintenance when required.

It is an object ofthis invention to provide a switch for electrical equipment which is easily and quickly disassemblable and repaired. It is also an object of this invention to provide a switch which is simple and rugged and which can be manufacturedv and assembled for a minimum cost.

These and other objects are accomplished in a simply constructed switch which requires only a few Simple operations to get it apart for repairs, and which is quickly and easily reassembled. Parts of the switch are mounted on blocks and can be removed as units by removal of the blocks. In the course of switch actuation, the contacts which make and break the circuit have a wiping action which assures good contact. Spring biased means are provided to return the switch to neutral or Switch-open position upon release of the actuating force.

In the drawings:

Fig. 1 is a view of `a switch made according to the invention with the end cover removed and with parts broken away and in section substantially on line I -I of Fig. 3.

Fig. 2 is a side elevation of some portions of the switch mechanism with parts broken away and in section in order to better display the switch structure.

Fig. 3 is a View in section on line 3-3 of Fig. 1.

Fig. 4 is a front elevation view of the switch showing the mechanism for holding the actuating means in the switch off-position.

Fig. 5 is a schematic diagram of the stationary and movable contacts and their relationship to eachother for the various switch positions, and

Fig. 6 is a partial front elevationA showing a modification of means for controlling the switch actuator I A casing]Y is shown as having a `plurality of mounting ears 4 for Lsecuring the casing to a piece of equipment on which it is to be used. The casins has@ end wall@ which is provided Q11 it-S inside surfafewith two threaded openings 8 and with abearinguboss I6. Four identical blocks I2 of electrically non-conductivexmaterial and hav#y ing iianges I3 at one lface thereof are secured in place on the inner surface o f Wall 6 by means of two threadedmembers I 4 engaging the holes 8. The blocks are assembled in the switchwith their flanges atopDOsite ends of each assembled pair. As is best seen in Fig, l, the blocks I2 are preferably hollow and generally resemble an isosceles triangle with a 4central `rib Hh One of the threaded members M passes through the blocks near what would be the intersection of the two equal' sidescf the triangle and the other threaded member Ill passes through the blocks near the intersectionof the base and the rib I perpendicular to the base c f thetriangle. The four blocks I2 are dividedup into pairs in which each pair supports on each of its equal sides, between the flanges I3, a yieldable contact, indicated generally at I8.

In each contact I8, a contact finger 20 is secured to a hinge member 22; as is shown in the drawings, the contact iinger 2 0 may be clamped between the hinge member 22 and a conductor bar 2li by means of screwsz. The hinge member 22 is rrecessed as shown at 28 to receive a hinge pin 30. The pin is carried on a bracket 32 which has a base 34 mounted on the non-conductive blocks by means of screws 36. The screws 36 extend through holes in adjacent insulating or non-conductive blocks. The center lines of the holes lie in the boundary plane between the two blocks, so that half of each hole is in each block. The screws 26 do not thread into the insulating blocks themselves,` but are threaded into holding members 33 inside the hollowV insulated blocks I. There are two members for each pair of blocks (one for each equal side) and each member lies adjacent the inside surface of one of the `equal sides, clamping a pair of adjacent blocks between' it andthe base 34 by means of the screws 36.

A spring l is placed in compression with its one end around a screw 3S and against the base 34 of bracket' S2.' and its other end against the upper end of hinge member 22.' Thusl the spring 40 biases the hinge member and accordingly the entire yieldable contact toward the axis of rotation 42 cf a movable contact, indicated generally at 44. The extent to which each yieldable contact I8 may be biased in the direction of movable contact 44 is limited by an abutment l provided at the lower end of the base 34 of bracket 32. A ilexible conductor strip 48, of braided copper orthe like, completes an electric circuit between the conductor bar 24 and an electric terminal 50. The terminal 50 is held in pla-ce by the upper one of screws 36 and is in good electrical contact with the strip 48.

The movable contact 44 is here shown as having limited rotational motion about an axis 42 referred to above. Movable contact 44 consists of a first contact element 52 and a second contact element 64. As is best seen in Fig. 3, the movable contact 44 is mounted on a shoulder 56 of a nonconductive hub 58. In order that the hub 58 and movable contact 44 may be rotated together Without relative rotation between the two, the central opening in the web 6b of the movable contact is preferably made of a polygonal shape, such as a hexagon, and of course the shoulder 6 is made of a corresponding con-figuration. Similarly the central opening 62 in the hub 58 is also preferably hexagonal to cooperate with the head 64 of a drive pin 66. The drive pin 66, hub 58, movable contact 44, and insulating or non-conductive bushing 68, and a collar 1U are held in assembled relation by means of a bolt 12 which is threaded into the right-hand end of the drive pin 66. As is evident from Fig. 3 of the drawings, the web 60 of the movable contact is clamped between the non-conductive bushing t8 and a cooperating iiange i4 on the hub 58. The collar 'l0 ts in a counterbore 'i6 in the non-conductive bushing 58 and thereby transmits the holding force of the bolt 'l2 to the bushing 58.

The drive pin '66 is keyed, as shown at 18, to an actuator 66. The actuator 8|! is slotted, as shown at B2 of Fig. 4, and the hub 84 of the actuator is tightly clamped about the drive pin 6G by means of a clamping bolt 66 extending across the slot 82. The actuator 86 carries a projection 88 extending inward toward the end wall 6 of the casing 2. An outward extending projection 90 on the casing serves as a stop member for the centering means described below.

Two rocker arms 92 and 94 are mounted to pivot on the hub e4 o1 actuator 86. The upper arm of rocker Q2 is connected to a spring 96 and the upper arm of rocker 94 is connected to a spring 98. Springs 96 and 9B are in tension, being mounted at their upper ends on bolts |09 and |il2 respectively. As is best seen in Figs. 2 and 3, bolts |60 and |02 provide clearance between their inner faces and the end wall to avoid pinching or clamping the ends of the springs; the latter are thereby permitted such limited rotational movement about the bolts as may be required by angular changes of the spring axes.

The spring 96 biases its connected rocker arm 92 clockwise, so that the lower arm of rocker 92 is biased against the right edge of stop projection 96, as seen in Fig. 4. At the same time, of course, rocker arm S2 brings pressure to bear against the projection 88 on the actuator 80. Similarly spring 8B biases its rocker arm 94 counterclockwise, so that the lower arm of rocker 94 is biased against the left edge of stop projection 90, as seen in Fig. 4, and at the same time the rocker arm 94 brings pressure to bear against the projection 88 on the actuator 88. Thus the two rocker arms 92 and 94 with their respective springs 96 and 93 form a centering device for the actuator B6, tending to hold the actuator in the position shown in the drawings, which is the neutral or open circuit position for the switch inasmuch as in this position the movable Contact 44 and the pivotable contacts I8 are out of engagement.

As will be well understood by those skilled in the art, the power connections for the switch may be brought into the casing by means of a cable H34 passing through a tangential opening |66 in the casing 2. The connections per se from the power cable |64 to the various terminals form no part of the invention and are neither shown nor discussed in detail here.

In order that the switch parts may be completely enclosed, a cover plate |88 is provided for the end of the casing opposite the end plate 6. As can be seen in Figs. 2 and 3, the cover plate |68 is preferably threaded in place and is secured against unscrewing by means of at least one lock screw IIE); a wire ||2 passes through openings in the cover |08 and in the screw ||0 and is preferably held together by means of any suitable seal ||4.

Fig. 6 shows an alternative design for control of the actuator, designated in this embodi-l ment. In Figs. 1 to 4 inclusive, the actuator 80 is automatically returned to the switch-open position upon the release of any force applied to the actuator'. In the embodiment shown in Fig. 6, the actuator |653 is provided with a notched sector |83 which cooperates with a holding device, indicated generally at |85. The holding device consists of a bracket |81 having a cylinder |89. A piston |9| is reciprocable in cylinder |89 and compresses a spring |93 between its upper end and the upper end of the cylinder. A small opening in the upper end wall of the cylinder assures free movement of the piston |9| without interference from entrapped air. The lower end of the piston lei carries a roller |91 which cooperates with the notches in the sector |83 to hold the actuator |80 in any selected one of a number of operating positions. A handle |99, threaded into the upper end of piston |91 extends through the end wall of the cylinder |89 and enables an operator to move the piston |9| in its cylinder without moving the actuator.

Operation To facilitate a discussion of the operation of the switch of this invention, the yieldable contacts all referred to generally by the reference numeral I8 in the above discussion are given individual reference characters A, B, C, and D. The circuit diagram of the movable and yieldable contacts shown in Fig. 5 is merely a developed view of the structure shown in mechanical detail in Fig. l. It is as though the movable contact 44 had been split radially inward from the contact element 54 approximateiy along the line 3--3 of Fig. l, and spread out to provide the diagram shown in Fig. 5.

To put the vehicle controlled by this switch into low speed-forward, the actuator B0 is moved counterclockwise, as seen in Fig. l, to the rst operating' position, in which the Contact element 52 engages yieldable contacts A and B. In this rst operating position, only the yieldable contacts A and B are engaged by the movable contact 44, In order to move the switch into high speed-forward, the operator continues the counterclockwise movement of actuator 8D to the second operating position. In this second position, yieldable contactsl A and B remain in engagement with the Contact element 52 and the contact element 54 engages the yieldable contact D. The Connections are thereupon effected for high speed-forward.

In moving the actuator 80 counterclockwise' as seen in Fig. 1, clockwise as seen in Fig. e', the operator causes the clockwise rotation of rocker arm 9.4V to increase the tension in spring S8. As the actuator 8G is moved clockwise in Fig. Li, the projection 88 on the actuator moves away from the` lower end of rocker arm 92. Rocker arm 92 is not able to follow the clockwise motion of actuatorv 8E). because its lower arm also engages the fixed stop or projection 90 on the casing. Thus when the actuator 80' is released the increased. tension in the spring 98 serves as a restoring force to return the actuator to to the switch-open position.

From this switch-open or neutral position, the switch may now be moved into low speedreverse by moving the actuator 8G clockwise, as seen in Fig. l. When the movable contact 44 is movedA into the iirst operating position in the reverse direction, the contact element 52 engages the yieldable contact C; the yieldable contact D is not engaged at this time by the Contact element 52, because contact element 52 is recessed or cut away, as shown at I I8 in Fig. 5. However, the contact element 54 engages the yieldable contact B, so that in the low speed-reverse position of the switch the movable contact 44 engages yieldable contacts B and C. To shift the switch into high speed-reverse, the actuator ti) is moved still further clockwise, as seen in Fig. i. Contact element 52 remains in engagement with yieldable contact C, and contact element t remains in engagement with yieldable contact B. In addition, contact element 52 comes into engagement with yieldable contact D. Accordingly, in the high speed-reverse position oi the switch, the movable contact cd engages yieldable contacts B, C, and D'.

in moving contact element 8e clockwise as seen in Fig. l, counterclockwise as seen in Fig. 4, the operator causes the projection 88 to move the rocker arm 92 counterclockwise, increasing the tension in spring 96. In a manner similar to that described above for the forward position, this tension in the spring S6 sets up a restoring force which returns the actuator 80 to the neutral or switch-open position upon its release.

When either Contact element 52 or 54 engages any yieldable contact i8, that contact is caused to pivot slightly about its pin 36, compressing its spring t0. The engagement between the contacts is such as to have a wiping effect of the yieldable contact on the movable contact, with pressure between the contacts caused by the spring 40 insuring good electrical engagement.

The construction of a switch made according to this invention is such that the switch is readily disassembled and reassembled. After unscrewing the cover plate E68, the operator need merely remove the two screws lli and disconnect the power leads from the terminals 50, in order to be able to remove the non-conductive blocks i2 in pairs and with them the yieldable contacts iS in pairs. rThe movable contact 44 is readily removed simply by unscrewing the bolt l2.

The operation of the embodiment shown in Fig. 6 involves the engagement of the roller E91 in the different notches of the sector 183 for the various operating positions of the actuator.

It will be readily understood by those skilled in the art that thisv invention provides a switch which is of a simple construction andv is readily disassembled for maintenance and may be quickly reassembled with a minimum of' idle time of the equipment. rIhe switchV isso constructed as to provide positive engagement between the contacts to insure good conductivity through the switch. Operation of the switch is simple and does not require a high degreey of skill. Other advantages will be readily apparent to those skilled in the art.

While there is in this application specically described two forms which the invention may assume in practice, it will be understood that these forms of the same are shown for purposes of illustration, and that the invention may be modined and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to-secure by Letters Patent is;

l. in a switch, a casing, a pair of identical hollow non-conductive blocks removably mounted side by side in the casing, a iirst contact, means inciuding a holding member inside said blocksfor mounting the Contact on the blocks, a second'contact in the casing movable into and out of engagement with the rst-named contact, and means including an actuator extending outside the casing for moving the second contact into and out oi engagement with the iirst Contact, and also including a projection on the actuator, anotherl projection on the casing, a rocker arm pivotally mounted outside the casing, and a spring connected to bias the rocker arm into engagement with both of said projections.

2. In a switch, a casing, a pair of identical hollow non-conductive blocks removably mounted side by side in the casing, a pair of contacts, means including a pair of holding members inside said blocks for mounting the contacts on opposite edges of the blocks, a movable contact in the casing having a Iirst and second contact element and being positionable into and out of engagement with the first-named contacts, and means including an actuator extending outside the casing for positioning the movable contact selectively into and out of conducting engagement with the rst-named contacts, and including also a projection on the actuator, another projection on the casing, a pair of opposed rocker arms pivctally mounted so as to be engageable with both projections, and spring means connected to bias the rocker arms into opposed engagement with the projections.

3. The switch set forth in claim 2, in which the movable contact is mounted for limited oscillatory movement and the electrical conducting engagement of the movable and first-named contacts includes two positons of the movable contact in one of which said iirst contact element engages one of the rst-named contacts and said second contact element engages the other of the first-named contacts, and in the other of which the engagement of the contact elements and the iirst-named contacts is reversed.

4. In a switch, a casing, a pair of electrically non-conductive blocks removably mounted side by side in the casing, a first contact, means including members passing between the blocks for mounting the contact on the blocks, a second contact in the movable into and out of conducting engagement with the first named contact, an actuator connected to move the second contact into a selected position, and spring means ,7 connected to bias the actuator into such a position that the contacts are disengaged, the last named means including a projection on the actuator, another projection on the casing, and a rocker arm biased into engagement with both projections.

5. The switch of claim 4, in which each of said blocks is provided with a peripheral flange at one face, the blocks being assembled in the switch with the two flanged faces at opposite ends, and the first-named contact being mounted between the flanges of the pair of blocks.

6. An electrical contact mounting comprising a casing, a pair of identical hollow blocks, each block being substantially an isosccles triangle having a hole at its Vertex anti another hole in its unequal side, inea-ns passing through the holes to secure the blocks in the casing with two adjacent faces thereof lying in a common contact surface, the mounted blocks having other holes therethrough with their axes lying substantially in said contact surface, electrical contact means, holding means inside the hollow blocks, and means engaging the electrical contact means and the holding means and passing through said other holes to support the electrical Contact means in operating position.

7. A mounting as in claim 6, in which each ablock has a rib extending from the vertex to the unequal side, the two first-named holes lying in the rib.

8. A mounting as in claim 7, in which each block has a peripheral iiange, the electrical contact means being mounted between the flanges of the pair of blocks.

9. A mounting as in claim 6, in which each block has a peripheral ilange, the electrical contact means being mounted between the flanges of the pair of blocks.

JAMES VJ. WOOLF.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,049,636 Abernethy Jan. 7, 1913 1,208,866 Weishaar Dec. 19, 1916 1,351,184 Morse et al. Aug. 31, 1929 1,909,549 Jensen May 16, 1933 2,239,155 evich Apr. 22, 1941 2,267,116 lvi'ageoch Dec. 23, 1941 2,276,674 Schroeder Mar. 17, 1942 2,462,777 Rappl Feb. 22, 1949 

